Electropneumatic brake control valve

ABSTRACT

An electropneumatic brake control valve unit capable of operating at the interface of the emergency brake portion or the service brake portion of a standard brake control valve as a retrofit unit or operating as a stand alone electropneumatic unit. The unit includes electric valves responsive to electrical signals and sensed brake pipe pressures to operate pneumatic valves to control the brake cylinder. The pneumatic valves are also operable independent of the electric control valves so as to allow braking with the electrical controls off or disabled. The unit can operate in combination with a complete brake control valve or with either or none of its emergency and service portions.

CROSS-REFERENCE

[0001] This is a Continuation of application Ser. No. 09/083,425 filedMay 21, 1998, which is a continuation of 08/708,984 filed Sep. 6, 1996,now U.S. patent application No. 5,967,620 issued Oct. 19, 1999.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] The present invention relates generally to electropneumatic(“EP”) brake control valves and more specifically, to a retrofoot unitto convert a pneumatic brake control valve to electropneumatic brakecontrol valve.

[0003] Electropneumatic brake control valves are well known in thepassenger railroad art and the mass transit railroad art. Because thetrains are short and are not involved generally in a mix and match at aninterchange of different equipment, the ability to provide pneumatic andelectrical control throughout the train has been readily available inthe passenger and the mass transit systems. In freight trains, thetrains may involve as much as 100 cars stretching over one mile or more.The individual cars may lay idle in harsh environments for up to a yearwithout use. Also, because of the long distance they travel, the carsare continuously moved from one consist to another as it travels to itsdestination. Thus, the use of electropneumatic-pneumatic valves in thefreight trains has been very limited.

[0004] A typical example of electropneumatic control on individual carsof a passenger train is U.S. Pat. No. 2,897,011 to Cotter. A magneticapplication valve and release valve are connected with the brake pipeand a control reservoir to locally produce a pneumatic signal simulatinga brake pipe signal to control the individual pneumatic control valve ateach of the cars.

[0005] The major use of electropneumatic valves in freight trains havebeen at the locomotive. This is where electric power is available andthe electrical interconnection is easy to achieve. Also, by the use ofradio waves, the simultaneous braking at various positions along thetrain using slave locomotives with electro-pneumatic valves has alsobeen used on freight trains. Recently, the American Association ofRailroads (“AAR”) has undertaken a massive study to determine anappropriate regime of incorporating electropneumatic valves on each ofthe cars of a freight train.

[0006] Various overlay systems have been proposed for use with controlvalves for freight trains. One is shown by U.S. Pat. No. 5,390,988 toShank. This is an overlay system wherein an adapter is inserted to theservice portion of a standard pneumatic brake control valve andelectrically operates pneumatic valves to pneumatically control astandard brake control valve. The overlay is inserted between theservice portion and its accelerated release valve portion. It is a pilotadaptor wherein the electropneumatic portion provides pneumatic signalsto the control valve to operate in its normal matter. The only directconnection of the electropneumatic portion and the brake cylinder is forgraduated release wherein the brake cylinder can be connected to exhaustthrough the electropneumatic valve.

[0007] Another overlay system is illustrated in U.S. Pat. No. 5,335,974to Klink. This system also includes an electronic module andelectropneumatic valves connected to a standard freight control valve. Apneumatic interface with transducers is provided between the serviceportion and the pipe bracket of a standard pneumatic brake controlvalve.

[0008] Another recent overlay system for a freight brake control valveis shown in U.S. Pat. No. 5,393,129 to Troiani et al. The two previouslydiscussed patents to Shank and Klink provided adaptors or overlay to theservice portion of the control valve or at the interface between theservice portion and the pipe bracket so as not to change the connectionof the train fluid system to the pipe bracket. Troiani et al. providestheir overlay at the connection of the pneumatic system to the pipebracket. The electropneumatic valve system is connected to the emergencyreservoir and between the retainer port of the pipe bracket and theretainer.

[0009] A train inspection apparatus is disclosed in U.S. Pat. No.2,993,199 to Browne et al. A pneumatic interface is provided between theemergency portion and the pipe bracket. This interface not only monitorsthe condition of the brake valve but also allows electropneumaticoperation or an overlay of the pneumatic operation of the pneumaticbrake valve. As with Shank and Klink, Brown et al. does not requiremodification of the connection of the fluid systems to the pipe bracket.

[0010] It is an object of the present invention to provide anelectropneumatic retrofit unit which can be mated with either theemergency or service portion pipe bracket interface.

[0011] It is another object of the present invention to provide anelectromagnetic retrofit unit for a pneumatic brake control valve whichcan operate as an overlay with a complete brake control valve or incombination with either the emergency or service portion, or as acomplete stand alone.

[0012] An even further object of the present invention is to provide anelectropneumatic unit for installation on new cars that is designed forelectropneumatic operation only.

[0013] These and other objects are achieved by an electropneumatic unitfor a pneumatic brake control valve connectable to an interface of theemergency brake portion or service brake portion of a standard pipebracket as a retrofit or by itself. The unit includes an EP interfacehaving an EP brake pipe port, EP brake cylinder port and an EP emergencyreservoir port for interfacing with the corresponding ports at the brakepipe interface. An electrical control valve, which is connected to theEP emergency reservoir port, has a venting port and an output port. Theelectrical control valve selectively connects its output port to theventing port for releasing a brake or connects the EP emergencyreservoir port to its output for applying the brake. A pneumatic brakecylinder valve is responsive to the output of the electrical controlvalve for selectively connecting the EP brake cylinder port with the EPemergency reservoir port or a venting port.

[0014] An isolation valve is connected to the brake cylinder valve forpreventing the output of the electric control valve from inadvertentlyoperating the brake cylinder valve. The isolation valve may be anelectrically controlled valve or a pneumatically controlled valve. Theisolation valve may connect the output of the electrical control valveto a venting port to thereby prevent the brake cylinder valve fromconnecting the EP brake cylinder port with the EP emergency reservoirport. The isolation valve may be responsive to a braking signal from thepipe bracket at an EP brake signal port or the brake pipe pressure, suchthat the pneumatic brake cylinder valve is responsive to the electricalcontrol valve when there is either no brake signal at the EP brakesignal port or the brake pipe is not being modulated for pneumaticbraking. The isolation valve may also connect the EP brake signal portto the EP brake cylinder port when preventing the output of the electriccontrol valve from operating the brake cylinder valve.

[0015] As an alternative, the isolation valve may also connect the EPbrake signal port to the brake cylinder valve to operate the brakecylinder valve when preventing the output port of the electric controlvalve from operating the brake cylinder valve. As a further alternative,the unit could include a pneumatic selection valve to selectivelyconnect the EP brake cylinder port either with the EP brake signal portor the output of the brake cylinder valve. The selection valve mayselect the higher of the two signals.

[0016] The control unit may also include a pneumatic emergency valveseparate from the isolation valve for selectively connecting the EPemergency reservoir port to the brake cylinder valve in response to anemergency signal in the EP brake pipe port. The pneumatic emergencyvalve is responsive to brake pipe recharging to cause the brake cylindervalve to release the brakes. The emergency valve and the selection valvemay be combined such that the emergency valve also disconnects theoutput port of the electric control valve from the brake cylinder valvein response to an emergency signal.

[0017] The unit may also include a charging choke and check valve whichallows the EP brake pipe port to charge an emergency reservoirs and/oran auxiliary reservoir connected to EP emergency reservoirs port and EPauxiliary reservoir ports through the unit. The unit may be connecteddirectly to and replace the service portion at the service portioninterface to the pipe bracket or may be connected through an adaptorplate to the emergency portion interface to the pipe bracket. When theunit is connected to the service portion, the emergency portion may beconnected to the pipe bracket and used as a vent valve. The emergencyportion may be replaced with a vent valve. Alternatively, the emergencyportion may also be removed and covered by a blank plate. The unitincludes one or more transducers for sensing pressure in one of the EPports and electronics on the unit for operating the electrical controlvalve and any other electrical valves in the unit.

[0018] The electropneumatic control unit may also be a separate standalone unit in combination with an electropneumatic brake systemindependent of a pneumatic brake valve. In addition to the interface andthe electrical control valve, it would include a pneumatic brakecylinder valve responsive to the output port of the electrical controlvalve for selectively connecting the EP brake cylinder port with the EPreservoir port or a venting port. This unit can also include a pneumaticemergency valve for selectively connecting the EP reservoir port to thebrake cylinder valve in response to an emergency signal in the EP brakepipe port. As in the other embodiment, the emergency valve may alsodisconnect the output port of the electrical control valve from thebrake cylinder valve in response to an emergency signal in the EP brakepipe port.

[0019] The unit may also include a release interface having a first andsecond brake cylinder port connected respectively to the EP brakecylinder port and to the brake cylinder valve or the selection valve formating with respective ports on a manual release valve to be mounted atthe release interface. Thus, the manual release valve can release thebrakes without draining reservoir pressure. The release interface alsoincludes a reservoir port interface so as so allow the manual releasevalve to also discharge the reservoirs.

[0020] In another embodiment, the electropneumatic control unit wouldinclude the EP interface and the electrical control valve in combinationwith the pneumatic isolation valve. The pneumatic isolation valve isresponsive to pressure in the EP brake pipe port for selectivelyconnecting the EP brake signal port and the EP brake cylinder port whenthe EP brake pipe pressure signals a brake application. The pneumaticisolation valve also connects the output of the electrical control valveto the EP brake cylinder port when the EP brake pipe pressure signalsthe brake release. Alternatively, the pneumatic isolation valve may beresponsive to pressure in the EP brake signal port and at the outputport of the electrical control valve for selectively interconnecting theEP brake signal port and the EP brake cylinder port when the EP brakesignal port pressure signals and brake application. The pneumaticisolation valve connects the EP emergency reservoir port to the EP brakecylinder port when the EP brake signal ports pressure signals a brakerelease and the output port of the electrical control valve signals abrake application.

[0021] Other objects, advantages and novel features of the presentinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a schematic of a train brake system on a carincorporating the principles of the present invention.

[0023]FIGS. 2A and 2B are schematic representations of a firstembodiment of an electropneumatic retrofit unit connected at theemergency and the service interfaces of a pipe bracket pneumatic brakecontrol valve respectively.

[0024]FIGS. 2C and D are schematic representations of electropneumaticunit as a stand alone without connection to any portion of a pneumaticbrake control valve with a standard pipe bracket and an electropneumaticpipe bracket respectively.

[0025]FIGS. 3A and 3B are schematic representations of a secondembodiment of an electropneumatic retrofit for a pneumatic brake controlvalve connected at the emergency portion of the interface to the pipebracket in combination with a complete brake control valve and only thepipe bracket respectively.

[0026]FIGS. 4A and 4B are schematics of a third embodiment of anelectropneumatic retrofit unit for a full pneumatic brake control valveconnected at the emergency interface of the pipe bracket in combinationwith a complete brake control valve and only the pipe bracketrespectively.

[0027]FIGS. 5A and 5B are schematics of a fourth embodiment of anelectropneumatic retrofit unit for a pneumatic brake control valveconnected at the emergency interface to the pipe bracket for use incombination with a complete brake control valve and only the pipebracket respectively.

[0028]FIGS. 6A and 6B are schematic representations of a fifthembodiment of an electropneumatic retrofit unit for pneumatic brakecontrol valves connected at the emergency portion interface of the pipebracket in combination with a complete brake control valve and a pipebracket only respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] As illustrated in FIG. 1, the train brake system includes a brakecontrol valve having a service portion 10 and emergency portion 20connected to a pipe bracket 30. A cut-off cock 12 connects brake pipe 14to the pipe bracket 30 at port BP. A retainer valve 18 connected toexhaust is connected to pipe bracket 30 at retainer port RET. A combinedreservoir 22, having an auxiliary AUX RES and an emergency reservoirEMER RES are connected to respective ports AR and ER of pipe bracket 30.A brake cylinder 24 is connected through empty/load device 26 to brakecylinder port BC. The elements described so far are part of a normalbrake system. The service portion 10, emergency portion 20 and pipebracket 30 are standard parts, for example, a DB-60 from New York AirBrake Corporation or Knorr Bremse AG. Similarly, they may be a ABDX orother AAR approved brake valves.

[0030] Although the schematic in FIG. 1 shows the service portion 10 andthe emergency portion 20 on opposing faces of pipe bracket 30, theinvention to be described can also be used on a single sided pipebracket where the service portion 10 and the emergency portion 20 areadjacent each other on a single face of the pipe bracket 30. It shouldalso be noted that the retrofit apparatus of the present invention mayalso be used with non-AAR valves and as stand alone units without thepipe bracket 30.

[0031] The retrofit unit of the present invention includes a car controldevice (CCD) 40 designed to provide electropneumatic brake control oneither a new or existing freight cars. An adaptor plate 42, connectedbetween the emergency portion 20 and the pipe bracket 30 is connectedpneumatically to the car control device 40 by passages 44. The adaptorplate 42 provides the interconnection between the pipe bracket 30 andthe emergency portion 20 as well as pneumatic access to certainpassages. Adaptor plate 42 includes a brake signal port CVC whichconveys the brake signal from the emergency portion 20 to the pipebracket 30 for the brake cylinder 24. It also includes a brake pipe portBPC connected to the brake pipe passage in adaptor plate 42. Theemergency port ERC is connected to a passage in adaptor plate 42connected to the emergency reservoir. The brake cylinder port BCC in theadaptor plate 42 is connected to a passage connected to the brakecylinder port at the interface with the pipe bracket 30.

[0032] An electrical or electronic empty/load device 46 is alsoconnected to the car control device 40. This provides a feedback to thecar control device 40 such that it can make appropriate decisions on theappropriate braking in combination with the pneumatic empty/load device26 or if the empty/load device 26 is not on the car. A caridentification device 48 is also connected to the car control device 40.This provides identification in a reporting system for each of theindividual cars. The car control device 40 is connected to trainlinecable 50 through junction box 52. The train cable 50 is a combinedcommunication and power line running through the train. Thecommunication and power line may be separate lines or one combined line.

[0033] Although the car control device 40 is shown connected to theadaptor plate 42 by passages 44, it may be mounted directly to or be anintegral part of the adaptor plate 42. As described in some of thepreferred embodiments, the EP ports on the car control device 40 areconfigured so as to mate directly with the interface ports on theservice side of the pipe bracket 30. This allows the car control device40 to replace a service portion 10 and be mounted directly to the pipebracket 30. The car control device 40 can be used by itself without theemergency portion 20 or in combination with the emergency portion 20also mounted directly to the pipe bracket 30. When the car controldevice is used by itself, it may be used with a standard pipe bracket 30or a special pipe bracket 30-1 as shown in FIGS. 2C and 2D respectivelywith a brake pipe vent valve. The adaptor plate 42 allows the carcontrol device 40 to be used with a complete brake control valve havingservice portion 10 and emergency portion 20.

[0034] The car control device 40 provides pneumatic control of the brakecylinder pressure when the brake pipe pressure is used as a supply line.The car control device 40 can also electropneumatically control thebrake cylinder pressure by providing the required functions of theservice portion when the brake pipe 14 is used as a control pipe. Whenthe car control device 40 is used with the complete brake control valvehaving service portions 10 and emergency portions 20, the car controldevice 40 provides pneumatic or electropneumatic control of the brakecylinder pressure. If the brake pressure is reduced at an emergencybrake rate, the car control device 40 will allow conventional brakeoperation using the service portion 10 and the emergency portion 20.This design of the car control device 40 allows it to operate either ina conventional fully pneumatic train or in a train having onlyelectropneumatic brakes. Also, it allows pneumatic back up if the carcontrol device fails or is without power.

[0035] When the car control device 40 substitutes for the serviceportion 10, it provides for charging of the emergency and the auxiliaryreservoirs. The car control device 40 also provides electropneumaticcontrol of the brake cylinder pressure. If the brake pipe is reduced ata service or an emergency rate or increased for a release, the carcontrol device 40 senses these pressure changes and simulates thefunction of the service portion 10 in controlling the brake cylinderpressure. When used in combination with the emergency portion 20, itacts as a back up for the emergency portion 20 or the emergency portion20 acts as a brake pipe vent valve. When the car control device is usedas a service portion or combined service/emergency portion and in atrain not having electropneumatic power or communication, the carcontrol device will require a power source on the car to electricallyoperate. Otherwise it will provide a more basic pneumatic response.

[0036] The car control device 40 has been designed specifically forretrofitting to a standard pipe bracket 30. The specific elements andlogic are also usable with the simpler pipe bracket and in anon-retrofit environment as illustrated in FIG. 2D.

[0037] Various embodiments of the car control device 40 will bedescribed in the following figures. Figure A will reflect the carcontrol device 40 used with a complete pneumatic control valve having aservice portion 10 and an emergency portion 20. FIG. B of the samefigure number will be the car control device partially modified tooperate with less than the complete pneumatic control valve incombination with either the emergency portion 20 or with neither theemergency portion 20 nor the service portion 10. FIGS. C and D show thecombination of car control device and vent valve.

[0038] To aid in understanding the various passages within the controlvalve, the brake pipe passage is represented by a “BD”, the brakecylinder passages by a “C”, the emergency reservoir passages by an “E”,the retainer passage by an “R”, the auxiliary reservoir passage by a“A”, and the control valve or brake signal passage from the emergencyportion for the brake cylinder by a “V”. The passages in the serviceportion 10 will have a number in the teens, the passages in the brakepipe 30 will have numbers in the 30's, the passages in the emergencysection 20 will have numbers in the 20's, and the passages in theretrofit adaptor plate 42 will have reference numbers in the 40's.

[0039] As illustrated in the figures, the pipe bracket 30 includes aservice portion interface 31 and an emergency portion interface 32. Eachinterface having interface ports connecting the brake pipe port BP brakecylinder port BC, the emergency reservoir port ER, retainer port RET andauxiliary reservoir port AR to interface service ports at face 31 andinterface emergency ports at interface 32.

[0040] The brake pipe port BP is connected by passage B30 to a filter 36in the pipe bracket 30. The filtered brake pipe air is provided to aservice interface port B31 and an emergency interface port B32. Thebrake pipe passage B30 is also provided to the emergency portion 20 forventing at interface port P34.

[0041] The brake cylinder port BC is connected by passage C30 to theemergency portion brake cylinder interface port C32. The brake cylinderpassage C31 in the pipe bracket 30 connects the brake cylinder interfaceport C33 on the service interface 31 to the brake cylinder interfaceports C34 and C36 on the emergency interface 32. This interconnects thebrake cylinder control signals between the service portion 10 and theemergency portion 20. The emergency reservoir port ER is connected bypassage E30 to emergency reservoir interface port E31 on the serviceinterface and E32 on the emergency interface. The retainer port RET isconnected by passage R30 to the retainer interface port R31 on theservice interface. The auxiliary reservoir port AR is connected bypassage A30 to the auxiliary interface port A31 on the serviceinterface. The pipe bracket 30 includes a quick action chamber 34connected to a quick action port Q32 at the emergency reservoirinterface. As previously described, the pipe bracket 30 and the passagesjust described are for a standard pipe bracket for AAR brake controlvalves.

[0042] The adaptor plate 42 provides access to the brake pipe emergencyreservoir, brake cylinder and brake control signal for the car controldevice 40 while providing continual interface between the pipe bracket30 and the emergency portion 20 at interfaces 32 and 32′ respectively.The adaptor plate 42 includes a quick action chamber passage Q42connecting quick action port Q32 at the pipe bracket to quick actionport Q22 at the emergency portion 20. Brake pipe passage B42 provides aninterconnection between the brake pipe ports B32 and B22 at theemergency portion and brake pipe respectively. Brake pipe passage B42 isalso connected to the brake pipe port BPC for the car control device 40by passage B41. Emergency reservoir passage E42 connects the emergencyreservoir port E32 at the pipe bracket interface to emergency reservoirport E22 at the emergency portion interface. Passage E41 connectspassage E42 to the emergency reservoir port ERC for the car controldevice 40. Passage C44 connects brake cylinder port C34 at the pipebracket to brake cylinder port C24 at the emergency portion. Brakecylinder passage C46 connects brake cylinder port C36 at the pipebracket interface to brake cylinder port C26 at the emergency interface.Brake pipe passage B44 connects brake pipe port B34 at the pipe bracketinterface to brake pipe port B24 at the emergency interface. Brakecylinder passage C41 connects the brake cylinder port C32 at the pipebracket interface to brake cylinder port BCC for the car control device40. Brake cylinder or brake signal passage B42 connects brake cylinderport C22 at the emergency portion to brake cylinder or brake signal portCVC for the car control device 40.

[0043] As in the previous figure, the service portion 10 and theemergency portion 20 are only shown in silhouette. Service portion 10 isshown with a standard manual release portion 28 mounted thereon.

[0044] The car control device 40 has a brake pipe port BPC, an emergencyreservoir port ERC, a brake cylinder port BCC and a brake signal portCVC connected by passages 44 to the respective ports on the adaptorplate 42. An auxiliary reservoir port ARC is also provided on the carcontrol device 40. The brake pipe port, emergency reservoir port, brakecylinder port and the emergency reservoir port are configured andpositioned so as to mate directly with respective ports on the serviceinterface 31 of the pipe bracket 30 so as to be used with the emergencyportion 20 as shown in FIG. 2B. Alternatively, the port configurationcould be configured to directly mount to the emergency interface 32 anda blanking plate provided on the service interface. Additionally, thecar control device 40 includes a combined emergency auxiliary reservoirand an emergency reservoir port AR/ER and first and second brakecylinder ports BC1 and BC2 at a release interface to mate with manualrelease valve 28 as shown in FIG. 2B. In FIG. 2A, a release portionblanking plate 402 is shown mounted blanking the port AR/ER. The passage404 interconnects brake cylinder ports BC1 and BC2 at the releaseportion interface.

[0045] The overall operation of the car control device 40 is to use thepressure in the emergency reservoir at port ERC to provide pressure atthe brake cylinder port BCC to control the braking by itself or as analternative, to use the brake signal at port CVC from the brake controlvalve. The car control device 40 is responsive to the signal from thebrake control valve at port CVC or the brake pipe port BPC to determinewhether to use an electrical control signal or the pneumatic signal fromthe brake control valve to operate the brake cylinder. In someembodiments, the brake pipe pressure at BPC is used to pneumaticallycontrol valve elements. In other embodiments, the pressure at the brakepipe port BPC is monitored electrically and thus, the control iselectropneumatic of the valves.

[0046] The first embodiment of the car control device 40-1, as shown inFIGS. 2A and 2B, include a brake cylinder valve or relay BCV connectedto the emergency reservoir port ERC via passage 406 and filter 408. Theoutput of the brake cylinder valve BCV is connected by passage 410 to aselect valve SEL which receives a second input from the brake signalport CVC via line passage 412. The brake cylinder valve BCV selectivelyconnects and disconnects the emergency reservoir port ERC to the selectvalve SEL. The output of the select valve SEL is provided to the brakecylinder port BCC via passages 414, 404 and 416 and screen 418. Theselect valve SEL selects the higher of the signals from the brakecylinder valve BCV and the brake signal port CVC and is illustrated as adouble check valve. Other types of valves which select the higher of thetwo signals may be used.

[0047] The brake cylinder valve BCV is illustrated on a three-positionvalve spring biased to the position shown wherein its output, thepassage 410, is connected to vent or exhaust EX and the input from theemergency reservoir port ERC on passage 406 is blocked. The pilotpressure in passage 420 forces the brake cylinder valve BCV against thespring to two of its other positions. In the middle position, all threeports of the valve BCV are blocked. On a high enough pressure signal, inthe third position, the output 410 of the valve BCV is connected to theemergency reservoir port ERC through passage 406. Thus, in the positionshown with exhaust in passage 410, the select valve SEL selects thebrake signal on port CVC for the brake cylinder port BCC. This allowsthe pneumatic brake control valve to control the brake cylinder.

[0048] An electrical control valve ECV is connected to the pilot line420 of the brake cylinder valve BCV via passage 422. The electricalcontrol valve ECV is illustrated as including a supply magnetic valveSUP and an exhaust magnetic valve EXH to selectively connect its outputport or passage 422 to either the exhaust EX or to the supply pressurewhich is from the emergency reservoir via passage 424 and 406. Thesupply valve SUP and the exhaust valve EXH are bias to their blockedposition. Thus, for an electrical off or electrical failure theelectrical control valve ECV will not provide a signal on passage 420and the brake cylinder valve BCV will remain in its inoperable positionhaving passage 410 vented. The electrical control valve ECV may also bea three-way proportional magnetic valve as illustrated in FIG. 3A.

[0049] These ECV valves are controlled by a microcomputer in order toapply, maintain or release the brake cylinder pressure. The brakecylinder valve BCV is preferably a relay valve and controls the brakecylinder pressure to amount equal to the pressure applied to its pilotport at 420. The magnetic valves are controlled with a modulated oranalog type of signal which allows the valves to be opened or closedproportionally rather than only fully opened or fully closed by usingdigital or on/off control signals. The straight lines on the port facessignify a proportional value. Alternatively, digital or on/off valvesmay also be used.

[0050] An isolation valve EPI is used to isolate electropneumaticcontrol of the brake cylinder valve BCV. The isolation valve EPI is atwo-position valve spring biased to connect its input from passage 428from output passage 434 connected to the pilot passage 420 of the brakecontrol valve BCV. The passage 430 in blanking plate 432 in a pilotoperated valve POV connects passage 428 to exhaust. The purpose of thepilot valve POV will be discussed with respect to FIG. 2B. The isolationvalve EPI is controlled by the microcomputer. During electricaloperation of the car control device 40, the isolation valve EPI ispositioned in its closed or energized position cutting off the exhaustfrom passage 430 in pilot port 420. This allows the electrical controlvalve ECV to control the brake cylinder valve BCV.

[0051] To allow pneumatic operation of the brakes using the brakecontrol valve or when the electrical of the brakes is to be cut out, theisolation valve EPI is de-energized into its opened position wherein theexhaust EX is provided to the pilot passage 420 causing brake cylindervalve BCV to assume the state illustrated in FIG. 2A. The primaryfunction of the isolation valve EPI is to prevent the car brakes frominadvertently applying during conventional service or when the car'selectrical control is cut out due to any leakage through the electricalcontrol valve EVC.

[0052] The emergency reservoir port ERC is connected to one of theblanked ports of the pilot valve POV via passages 406, 436 and choke438. The brake pipe port BPC is connected via passage 440 and screen 442to the blanked pilot port of pilot valve POV. The operation of the pilotvalve POV will be described with respect to FIG. 2B. A charging checkand choke valve CC, illustrated in FIG. 2B, has a blanking plate 444 inFIG. 2A and is connected to the brake pipe port BPG and passage 440 bypassage 446. The charging check and choke CC is also connected viapassage 448 to the emergency reservoir port ERC and to the auxiliaryreservoir port ARC via screen 450. Passage 452 connects the emergencyreservoir port ERC and auxiliary reservoir port ARC to the release valveblanking plate 402. The ability to charge the emergency reservoir andthe auxiliary reservoir via the brake pipe and charging check and chokeCC will be described with respect to FIG. 2B.

[0053] Car control device 40 includes brake pipe transducer BPTconnected to passage 440, brake cylinder transducer BCT connected topassage 416, emergency reservoir transducer ERT connected to passage 406and a port 16 transducer 16T connected to the output 420 of the electriccontrol valve ECV. The microcomputer of the car control device 40 usesthese measured values from the pressure/voltage transducers to performthe required operation of the electric portion of the control device.

[0054] The operation of the car control device 40-1 illustrated in FIG.2A will now be described.

CHARGING

[0055] During brake pipe charging, brake pipe pressure enters brake pipeport BP on the pipe bracket 30 and flows to the service portion 10 andemergency portion 20 which operate in their typical manner. As brakepipe pressure is increased, the brake control valve charges itsauxiliary and emergency reservoirs. As the emergency reservoir pressureincreases, air flows from port ERC of the adaptor plate 42 to port ERCof the car control device 40-1. Pressure from the emergency reservoirport ERC flows via passages 406 and 424 to the electrical valve ECVwhere it is blocked and via 406 to the brake cylinder valve BCV where itis also blocked.

[0056] Brake pipe pressure from brake pipe port BP of the pipe bracket30 also flows from the adaptor plate port BPC to the car control devicebrake pipe port BPC where it is blocked at the charging check/choke CCCand the pilot valve POV. In the release/charging position, the brakecontrol valve's brake cylinder pressure at port CVC is zero. Thus, thepressure on adaptor plate 42 and the car control device 40-1 at port CVCare zero. The isolation valve EPI is positioned by activation todisconnect passage 420 from exhaust and allows the electrical controlvalve ECV to control passage 420 of the brake cylinder valve BCV. Theelectrical control valve ECV in its release position, controls itsoutput to zero psi and the brake cylinder valve BCV controls its output422 to zero PSI and therefore the brakes remain released with zero psiat brake cylinder port BCC.

CONVENTIONAL SERVICE BRAKE APPLICAITON

[0057] For conventional pneumatic brake application, the train operatorreduces the brake pipe pressure in a normal manner. The brake controlvalve provides a corresponding output to the port CVC of the adaptorplate 42 to the car control device 40. The microcomputer of the carcontrol device senses the drop in brake pipe pressure by brake pipetransducer BPT and maintains the isolation valve EPI de-energized suchthat passage 420 of the brake cylinder valve BCV remains exhausted intothe position shown in FIG. 2A. The brake control valve BCV connectspassage 410 to the select valve SEL to exhaust and allows the brakingsignal on port CVC from the brake control valve to be transmitted viapassages 414, 404 and 416 to the brake cylinder port BCC of the adaptor42 and subsequently to the brake cylinder port BC of the pipe bracket30.

ELECTROPNEUMATIC SERVICE BRAKE APPLICATION

[0058] For an electropneumatic brake application, the train operatormaintains the brake pipe pressure at a constant value, at a fullycharged level, and commands an electropneumatic brake application fromthe locomotive. The microcomputer on each car control device 40 receivesthe electric brake application signal. The isolation valve EPI isactivated and maintained activated during electropneumatic brakeapplication. The activated isolation EPI disconnects passages 434 and420 from exhaust and blocking passage 434. The electric control valveECV is energized and a corresponding amount of emergency reservoirpressure from port ERC via passages 406, 424, choke 426, passage 422 issupplied to the control passage 420 of the brake cylinder valve BCV. Thebrake cylinder valve BCV provides an amount of emergency reservoirpressure equal to that on passage 420 to the select valve SEL viapassage 410 and on to the brake cylinder port VCC via passage 414, 404and 416. Since the brake pipe is fully charged, there is zero pressureat the brake signal port CVC.

[0059] In this method, either a full brake application or a graduatedbrake application can be achieved. The transducer 16T provides electricfeedback to the microcomputer which controls the electric control valveECV to provide a pressure corresponding to the brake cylinder pressuredesired. As is well known, the amount of brake cylinder pressure applieddepends on the train brake command as well as the car weight. As shownin FIG. 1, the microcomputer of the car control device 40 may receive anelectric feedback signal of the car weight from sensor 46.

EMERGENCY BRAKE APPLICATION

[0060] For an emergency brake application, the train operator can eithermake an emergency rate of emergency pipe reduction or anelectropneumatic emergency brake application. For a pneumatic emergencybrake application, the car control device will operate as described fora regular pneumatic brake application. The isolation valve EPI isdeenergized and prevents the brake cylinder valve BCV from providing apressure signal to the select valve SEL. The emergency brake signal fromthe brake control valve at port CVC is provided via passages 412, 414,404 and 416 to the brake cylinder port BCC.

[0061] For an electropneumatic emergency application, the operation isthe same as described for an electropneumatic service operation. Theisolation valve EPI is activated and the electric control valve ECV isoperated to produce the desired control pressure over passages 422 and420 to control the brake cylinder valve BCV to provide an appropriatepressure over passage 410 to the select valve SEL. The signal isprovided via passages 414, 402 and 416 to the brake cylinder port BCC.

[0062] If the brake pipe experienced an emergency rate of brake pipereduction while the electropneumatic control using the electric controlvalve ECV is making a service application, the car control device 40-1will go into an emergency application mode. The microcomputer willsense, by the brake pipe transducer BPT, that there is an emergency rateof reduction and will maintain the valve ECV in its supply condition tomaintain the brake cylinder valve BCV on to provide an emergencyapplication build up at the brake cylinder port BCC. If the electricalcontrol system cannot build up the pressure fast enough, the pneumaticbrake signal from the brake control valve at port CvC will be selectedby the select valve SEL to build up an emergency pressure in the brakecylinder at brake cylinder port BCC. Thus, the brake control valve andthe electropneumatic portion of the car control device 40 operate inparallel, with the higher of the two signals provided by select valveSEL, to build up the pressure in the brake cylinder in response to anemergency rate of reduction in the brake pipe.

CONVENTIONAL RELEASE

[0063] In order to make a conventional pneumatic brake release, thetrain operator increases the brake pipe pressure in the normal manner.The brake control valve releases the brake cylinder by venting the brakecylinder port BC. This results from connecting the brake signal port CVCto the atmosphere. The rise in the pressure in the brake pipe is sensedby transducer BPT and used by the microcomputer to assure that theisolation valve EPI is deactivated such that the control port in passage420 for the brake cylinder valve BCV is connected to exhaust. Thisprovides protection against any leakage through the electrical controlvalve ECV from causing undesired brake application while the car isbeing operated in a conventional release mode. Thus, both sides of theselect valve SEL is connected or vented to exhaust.

ELECTROPNEUMATIC BRAKE RELEASE

[0064] In an electropneumatic brake release, the train operator retainsthe brake pipe pressure at a constant level and electrically commands abrake release from the locomotive. The microcomputer in the car controldevice 40-1 receives the electric brake release signal and operates itselectric control valve ECV. The electric control valve ECV exhausts acorresponding amount of emergency reservoir pressure from passages 422and 420. This drop in pressure moves the brake cylinder valve BCV fromits center block or lap position to its bottom position connectingpassage 410 to exhaust. This will cause brake cylinder pressure frombrake cylinder port BCC to be reduced through passages 416, 404, 414through select valve SEL and passage 410. The signals from brakecylinder transducer BCT and the pilot brake control signal on transducer16T are used by the microcomputer to control the desired reduction inpressure. Once the desired reduction is achieved, the brake cylindervalve BCV is moved to its centered block position. In this manner,either a full brake release or a graduated brake release can be achievedelectropneumatically.

[0065] The car control device 40-1 in FIG. 2A may be used as a directreplacement for the service portion 10 of the brake control valve asillustrated in FIG. 2B or without service portion 10 or emergencyportion 20 as illustrated in FIG. 2C and D. Referring to FIG. 2B, theblanking plate 444 is removed from the charging check CC and replacedwith a charging choke 454 and a charging choke valve 456. This allowsthe brake pipe pressure at brake pipe port BPC to charge the emergencyreservoir at port ERC and the auxiliary reservoir at port ARC.

[0066] The blanking plate 432 for the pilot valve POV is removed and apilot valve POV is provided to pneumatically sense an emergency pressurein the brake pipe and initiate a pneumatic brake application. The pilotvalve is responsive to the brake pipe port pressure at BPC toselectively connect the isolation valve EPI to either exhaust or to theemergency reservoir port ERC. When the brake pipe pressure is greaterthan approximately 50 PSI, for example, the pilot valve POV connectspassage 428 and the isolation valve EPI to exhaust. When the brake pipepressure is less than approximately 50 PSI, the pilot valve POV connectsthe emergency and auxiliary reservoirs to passage 428 of the isolationvalve EPI through a choke 438 and passages 436, 428.

[0067] Thus, when the brake pipe pressure is above approximately 50 PSI,the pilot valve POV connects passage 428 to exhaust and theelectropneumatic control operating on brake cylinder valve BCV is thesame as that described for FIG. 2A. When the brake pipe pressure isreduced below 50 PSI, and the isolation valve EPI is deactivated,reservoir pressure is provided to passage 420 to operate the brakecylinder valve BCV to apply reservoir pressure to the select valve SELand subsequently to the brake cylinder port BCC to apply the brakes. Inthis manner, a pneumatic emergency brake application is available if thebrake pipe has been reduced sufficiently and if the car control device'selectronics has been turned off. This condition occurs when the train isparked or when the car control device's electronics fail.

[0068] Another modification is that a blanking plate 458 has replacedthe select valve SEL such that passage 410 is always connected topassage 414 and through 416 to the brake cylinder port BCC. Passage 412is also connected to passage 414 but the brake signal port CVC isblanked at the service interface 31 of the brake pipe 30.

[0069] The blanking plate 402 is removed and a manual release valve 28is connected to the ports AR/ER, BC1 and BC2. As is well known, theports BC1 and BC2 are interconnected through the release valve 28. Themanual release valve 28 allows manual release of the brake cylinder byconnecting the port BC2 to exhaust without draining the reservoirs.Also, the manual release 28 can also connect the auxiliary and emergencyreservoirs through port AR/ER to exhaust.

[0070] The car control device 40-1 replace the service section 10 andprovides an interface between the release valve 28 and the pipe bracket30. The position of the ports BPC, ERC, BCC and ARC mate directly withthe corresponding port B31, E31, C33 and A31 on the service interface 31of the pipe bracket 30. No adaptor plate is needed. The brake signalport CVC is blanked at the interface 31 as is the retainer port R31.

CHARGING

[0071] During brake pipe charging, the brake pipe pressure at port B31,BPC flows through the charging check valve and choke CC to charge boththe auxiliary reservoir and the emergency reservoir through portsARC/A31 and ERC/E31. As the reservoir pressure increases, air flowsthrough passage 406 to the brake cylinder valve BCV and the electriccontrol valve ECV where it is blocked. Brake pipe pressure also flows onpassage 440 of the pilot port of pilot valve POV which, at approximately50 PSI, moves from the position shown to connect isolation valve EPI toexhaust. If BP is below 50 PSI, the brakes will be applied. Reservoirpressure in passage 436 through pilot valve POV passage 428, deenergizedisolation valve EPI and passage 434 to the control port passage 420 ofbrake cylinder valve BCV prior to the brake pipe pressure exceedingapproximately 50 PSI operates the brake cylinder valve BCV to its thirdposition which would connect the emergency reservoir or auxiliaryreservoir to the brake cylinder port BCC. Alternatively, themicrocomputer would activate isolation valve EPI and electrical controlvalve ECV to apply reservoir pressure to the control port passage 420 ofthe brake control valve BCV to apply the brakes when transducer BPTsenses a brake pipe pressure below approximately 50 PSI.

[0072] Once the brake pipe has reached approximately 50 PSI asdetermined by the transducer BPT, the microcomputer activates theelectrical control valve ECV so as to connect passages 422 and 420 toexhaust. This maintains the brake control valve BCV in the shownposition with passage 410 connected to exhaust. This maintains the brakecylinder port BCC at exhaust through passages 416, the manual releasevalve 28, passage 414 and passage 410 and releases the brakes.

ELECTROPNEUMATIC BRAKE APPLICATION AND RELEASE

[0073] The operation of the car control device 40-1 for electropneumaticbrake application release is the same as that described in FIG. 2A. Theelectrical control valve ECV controls the signal to control passage 420for the brake cylinder valve BCV which selectively connects its output410 and subsequently the brake cylinder port BCC to a) exhaust forrelease, b) blocked to maintain or lap the brake pressure in the brakecylinder or c) application which applies pressure from passage 406 fromthe emergency reservoir port ERC and the auxiliary reservoir port ARC toits output 410 and subsequently the brake cylinder port BCC. Theelectrical operation is when the brake pipe being maintained at aconstant pressure and the electrical control signals are provided to thecar control device 40-1.

CONVENTIONAL PNEUMATIC APPLICATION

[0074] Since the car control device 40-1 has replaced the serviceportion 10 of the brake control valve, it may provide the appropriateresponse to variations in brake pipe pressure without input from acentral controller. Thus, when the car is used in a conventional train,the operator modulates the brake pipe pressure to control the brakes.The car control device 40, senses variation of the brake pipe pressureby the brake pipe transducer BPT and performs the appropriate operation.Since a conventional train does not have a train powerline, the car musthave an independent power source.

[0075] When the microcomputer senses a service brake application in thebrake pipe, it controls the electrical control valve ECV to provide anappropriate signal on passage 420 for the brake cylinder valve BCV toapply the desired pressure to the brake cylinder port BCC. The brakecylinder valve BCV provides air stored in the emergency and auxiliaryreservoirs to the brake cylinder. Once the appropriate pressure isprovided to the brake cylinder, the microcomputer through the electricalcontrol valve ECV brings the brake cylinder valve BCV to its center orlapped position.

[0076] During conventional service brake application, the brake pipereduction is different depending upon the length of the train and thebrake valve handle position. Therefore, it is necessary for the carcontrol device 40-1 to be able to change its brake cylinder build uprate depending upon the brake pipe reduction rate. The car controldevice 40-1 will control the brake cylinder pressure corresponding tothe rate at which the sensed reduction in the brake pipe is made usingthe electrical control valve ECV. The electrical valve ECV is a analogtype of device which provides a control proportional both to its inputsignals value and its rate of change. The car control device can bedesigned to mimic the operation of a conventional pneumatic brakecontrol valve at its car. The car control device operation and theresulting operation of the brakes on the car will be no different thanthe pneumatic only brakes and thus, invisible to the operator.

[0077] For an emergency rate of change of the brake pipe pressure sensedby transducer BPT, car control device 40-1 will operate electric controlvalve ECV and isolation valve EPI to control the brake cylinder valveBCV to apply an emergency application to the brake cylinder port BCCusing the emergency reservoir and the auxiliary reservoir. The emergencyportion 20 connected to the pipe bracket 30 connects the brake pipe portBP to exhaust in response to an emergency rate of decrease of brake pipepressure to propagate the emergency brake pipe pressure reductionthrough the train.

[0078] The emergency portion 20 will operate normally to alsopneumatically connect the emergency reservoir to the brake cylinder portBC. Thus, the car control device 40-1 must operate the electricalcontrol valve ECV and the isolation valve EPI to move the brake cylindervalve BCV from the position shown in FIG. 2B where the EP brake cylinderport BCC is connected to exhaust to either its middle lap position or toits upper applied position where emergency reservoir pressure is appliedto the EP brake cylinder port BCC. Otherwise, the car control device40-1 will connect the brake cylinder to an exhaust through the emergencyportion 20 and try to release the brake. The car control device 40-1 canoperate the brake cylinder valve BCV by either using the electricalcontrol valve ECV with the isolation valve EPI activated or deactivatingthe electric isolation valve EPI and allowing the pilot or emergencyvalve POV to respond to the brake pipe pressure. This regime for FIG. 2Bis necessary since the select valve SEL does not have the ability toselect between the brake signal coming from the emergency portion 20 andthe output of the brake cylinder valve BCV.

[0079] The car control device 40-1 also operates when it is turned offor without power to respond to an emergency brake application. Once thebrake pipe pressure is dropped below 50 PSI, the pilot valve POV willassume the position shown in FIG. 2B. This connects the emergency andauxiliary reservoir ports ERC and ARC respectfully to passage 428. Withthe car control device off, the isolation device EPI is in its shownposition which interconnects passage 428 to passage 434 and 420 tocontrol the brake cylinder valve BCV to its third position. Thisinterconnects passage 406, which has the emergency reservoir andauxiliary reservoir connected thereto through to the output passage 410of the brake cylinder valve BCV. This will apply the full reservoirpressure to the brake cylinder port BCC through the select valve SELpassage 414, release valve 28 and passage 416.

CONVENTIONAL PNEUMATIC RELEASE

[0080] In response to a conventional release, the increase of thepressure in the brake pipe is sensed by transducer BPT and provided tothe microcomputer which controls the electrical control valve ECV toprovide an appropriate signal to the brake cylinder valve BCV to reducethe brake cylinder pressure in a full release or graduated release mode.In response to a recharging of the brake pipe after an emergencycondition, the pilot valve POV will also change states from its appliedposition shown in FIG. 2B to its exhaust position after the brake pipeexceeds approximately 50 PSI as previously described.

[0081] As a further alternative to FIG. 2B, the emergency portion 20 maybe removed a blanking plate placed at an emergency portion interface 32of pipe bracket 30 as illustrated in FIG. 2C. Also, the car controldevice 40-1 may operate as a totally stand alone device even without thepipe bracket 30 or a modified pipe bracket illustrated in FIG. 2D. Sincethe electrical control valve ECV can perform service and emergencyapplications and release in response to electrical signals and pneumaticsignals, the emergency portion 20 is not needed. Also, as previouslydescribed, the pilot valve POV being responsive pneumatically to brakepipe pressure can also apply pneumatically in an emergency applicationif the electronic portion of the car control device 40 is off orinoperable.

[0082] If the emergency portion 20 is removed and a blanking plate 56 isprovided for the standard pipe bracket 30, a vent valve 54 would have tobe connected to the brake pipe as shown in FIG. 2C. The vent valve 54, aKm-2, for example, is responsive to an emergency rate of brake pipereduction to locally vent the brake pipe. This performs the samepropagation function as the emergency portion 20 of a brake controlvalve. The blanking plate 56 includes a passage 58 interconnecting brakecylinder port C32 and C34 on the emergency portion interface 32 of pipebracket 30. This connects the brake cylinder port BC and passages C30and C31 in the pipe bracket 30.

[0083] The car control device 40-1 may also be used with a modified pipebracket 30-1 as illustrated in FIG. 2D. The reservoir 22 may be a singlesupply reservoir as shown. Thus, there is a single port SR on the pipebracket 30-1 instead of an emergency port ER and an auxiliary reservoirAR. Also, since there is no service portion, the retainer port RET hasalso been deleted. The first interface 31-1 with the car control device40-1 has been simplified to having brake pipe port B31 connected throughfilter 36 and brake pipe passage B30 to the brake pipe port BP, supplyport E31 connected to supply port SR through supply passage E30 and abrake cylinder port C33 connected by passage C30 to the brake cylinderport BC. It should also be noted that the quick action chamber 34 hasbeen deleted. The second interface 32-1 of the pipe bracket 30-1includes a vent valve 54 connected to brake pipe port B32. The bracket30-1 may be provided on newer cars or may be substituted for thestandard pipe bracket 30 on existing cars. The operation of the unit isidentical to that in FIG. 2C.

[0084]FIGS. 3A and 3B show a second embodiment of the car control device40-2. Those elements and passages having the same function as that inthe first embodiment 40-1 have the same reference numbers. The carcontrol device 40-2 shows the electric control valve ECV as a singlethree position valve instead of the pair of magnetic valves at 40-1. Thetwo lines along the face of the valves indicated that it is aproportionally positionable valve. The car control device's 40-2isolation valve EPI, as shown in FIG. 3A, is the pneumatically operatedisolation valve 462 instead of electrically operated as in the carcontrol device in 40-1. A passage 460 connects the brake signal port CVCand the passage 412 as the pilot or control for the isolation valve 462.The isolation valve EPI is spring biased to its closed positiondisconnecting passage 434 and 420 from exhaust. This allows theelectrical control valve ECV to operate to control the brake cylindervalve BCV. When a brake control signal appears at port CVC from thebrake control valve, it moves the isolation valve EPI from the positionshown to its second position which connects passage 434 and 420 toexhaust. This isolates the electrical control valve ECV from operatingthe brake cylinder valve BCV. Thus, the pneumatic brake control valvetakes precedence over the electrical control valve ECV in providing thebraking signal to the brake cylinder.

[0085] A further modification of the car control device 40-2, is arelief valve 464 connected to passage 414 of the brake cylinder portBCC. Thus, if the brake cylinder pressure becomes excessive, the reliefvalve 464 will vent some of that pressure to exhaust.

[0086] The blanking plate 444′ includes not only blanking passages butthe charging choke 454 and the charging check 456. In the positionillustrated in FIG. 3A, passage 446 from the brake pipe port BPC isblocked and not connected to passage 406 for the emergency reservoirport ERC. Installation of the blanking plate 444′ in its secondposition, as illustrated in FIG. 3B, connects the charging choke 454 andcharging check 456 between passages 446 and 406 to allow charging of theemergency reservoir from the brake pipe through the car control device40-2.

[0087] The operation of the car control device 40-2 of FIG. 3A is thesame as that for the first embodiment 40-1 of FIG. 2A, except that theisolation valve EPI is pneumatically operated in response to a brakecontrol signal on port CVC. As in FIG. 2A, the car control device 40-2in FIG. 3A is used in combination with a full brake control valve havingservice portion 10, emergency portion 20, pipe bracket 30 and adaptorplate 42. As previously discussed, the car control device 40-2 may beconnected to the adaptor plate 42 by pneumatic lines 44 or mounteddirectly thereto and being an integral part thereof.

[0088] The car control device 42-B can also be used as a stand aloneelectropneumatic device. As illustrated in FIG. 3B, the car controldevice 40-2 is connected through adaptor plate 42 to the pipe bracket 30at the emergency portion interface 32. The service portion 10 has beenreplaced by blanking plate 476 and the emergency portion 20 has beenreplaced by the blanking plate 478. As in the first embodiment for thecar control device 41-1, the second embodiment 40-2 replaces the selectvalve SEL with a blanking plate 458 to connect the output passage 410 ofthe brake cylinder valve BCV directly to the brake cylinder passage 414.As previously discussed, the blanking plate 444′ is rotated so as toconnect the charging choke 454 and the charging check 456 between thebrake pipe port BPC and the emergency reservoir cylinder port ERC. Thisallows charging of the emergency reservoir from the brake pipe throughthe car control device 40-2.

[0089] Another modification to the second embodiment to the car controldevice 40-2 between FIGS. 3A and 3B is that the isolation valve EPI hasbeen modified to be a combined isolation and pilot valve EPI/POV. Theisolation valve 462 has been replaced by an isolation valve 466 andregulator valve 468. Valve 466 is a two-position valve responsive to apilot signal from the brake pipe port passage 440. Regulator valve 468is connected to the emergency reservoir port ERC via passages 406 and436. Regulator valve 468 is responsive to emergency reservoir pressureto apply the emergency reservoir pressure via passage 470 as an input tothe valve 466.

[0090] Valve 466 is responsive to brake pipe pressure at brake pipe portBPC via passage 440. As discussed for the pilot valve POV in theembodiment 40-1, valve 466 is spring biased to connect the emergencyreservoir to the brake cylinder valve control port passage 420 to applyan emergency level of brake pressure to the brake cylinder through thebrake cylinder valve BCV. Once the brake pipe pressure has exceeded, forexample, 50 PSI, valve 466 moves to its second position connecting theoutput of the electrical control valve ECV and passage 422 to passage420 to control the brake cylinder valve BCV. Thus, it can be seen thatthe valve 466 is a combination of the isolation valve EPI and the pilotvalve POV of the first embodiment illustrated in FIG. 2B. Also, since itis responsive to an emergency condition in the brake pipe to apply thebrake, it can be considered an emergency application valve.

[0091] Thus, the second embodiment of the car control device 40-2 inFIG. 3B operates the same as the first embodiment 40-1 illustrated inFIG. 2-B. The major exception being that there is no emergency portion20 connected to the pipe bracket 30 and the car control device 40-2 isconnected to the pipe bracket using the adaptor plate 42 instead ofbeing connected directly at the service portion interface 31. Aspreviously discussed, since the emergency portion is not available, avent valve 54 must be provided. The second embodiment 40-2 may also beoperated in combination with an emergency section and therefore no ventvalve would be required. Similarly, the second embodiment 40-2 can bemodified to be mounted directly to the service interface 31 of the pipebracket. As in the first embodiment of 40-1, a port would have to beprovided for the auxiliary reservoir such that it could be charged fromthe brake pipe. Similarly, if desired, the manual release interfacecould have to be added to the embodiment 40-2. The embodiment of FIG. 2Bfor the car control device 40-1 may be modified to remove the manualrelease valve 28. It should be noted in FIG. 3B that the relief valve464 has been removed and its port blanked.

[0092] A third embodiment of the car control device 40-3 is illustratedin FIGS. 4A and 4B. The third embodiment 40-3 is similar to the secondembodiment 40-2 in that it is designed for use with the adaptor plate 42and not specifically for use on the service interface 31 with the pipebracket. Thus, the porting for the auxiliary reservoir and the manualrelease valve are not provided. As with the previous embodiment, carcontrol device 40-3 can be modified to provide this additional porting.Although the third embodiment 40-3 uses a pair of magnetic valves forthe electrical control valve ECV versus a single valve illustrated inembodiment 40-2, either type of electrical control valve may be used.The major distinction between the third embodiment 40-3 and the secondembodiment 40-2 is that in 40-3 the isolation valve EPI and theselection valve SEL have been combined into a single valve. The thirdembodiment 40-3 also incorporates the combined isolation and pilot valveEPI/POV in FIG. 4B as the second embodiment 40-2 in FIG. 3B.

[0093] As illustrated in FIG. 4A, the car control device 40-3 isconnected to the adaptor plate 42 in combination with a completepneumatic brake control valve. Thus, the pilot valve POV is not neededin a blanking plate 480 is provided connecting the output passage 442 ofthe ECV valve directly to the control passage 420 for the brake cylindervalve BCV. The blanking plate 480 blanks the passage 440 from the brakepipe port BPC and passage 436 from the emergency reservoir port ERC. Thecombined isolation select valve EPI/SEL is responsive to the pressurefrom the brake signal port CVC and passage 412 to simultaneously selectthe brake signal at port CVC and passage 412 over the signal from thebrake cylinder valve BCV and passage 410 to be connected to its outputpassage 414 for the brake cylinder port BCC and to connect passage 434which is connected to the control passage 420 of the brake cylindervalve BCV to exhaust. This prevents the electric control valve ECV fromoperating the brake cylinder valve BCV. The EPI/SEL valve is shown inits first position where there is no brake signal or pressure on brakesignal port CVC and passage 412. This connects the output 410 from thebrake cylinder valve BCV to the brake cylinder port BCC through passage414. The passage 434 connected to the control passage 420 for the brakecylinder valve BCV is blanked.

[0094] As illustrated in FIG. 4B, the third embodiment 40-3 may also beused as a stand alone valve wherein blanking plates 476 is substitutedfor the service portion and blanking plate 478 is substituted for theemergency section 20. As previously described for the second embodiment40-2, the emergency portion may be provided to act as a vent valveresponsive to emergency brake pipe pressure. If the blanking plate 478is used, a brake pipe vent valve 54 must be provided. In thisembodiment, the combined isolation select valve EPI/SEL is removed and ablanking plate 482 is provided. The blanking plate 482 directly connectsthe output passage 410 of the brake control valve BCV to the passage 414connected to the brake cylinder port BCC. The passage 412 from the brakesignal port CVC and passage 432 are blanked.

[0095] Also, the blanking plate 480 is removed for the combinedisolation and pilot valve EPI/POV. The valves 466 and 468 are providedas the combined isolation pilot valve EPI/POV. This is the samestructure as in the second embodiment 40-2 illustrated in FIG. 3B. Thus,the operation is the same to control the brake cylinder valve BCV eitherelectrically in total or pneumatically in response to an emergency brakepipe application.

[0096]FIGS. 5A and 5B illustrate a fourth embodiment of the car controlvalve 40-4. As in the third embodiment 40-3, illustrated in FIGS. 4A and4B, the select valve SEL is either eliminated or combined with theisolation valve EPI. In FIG. 5B, the pilot valve and isolation valve arecombined as EPI/POV in FIG. 4B. The major difference between the carcontrol device 40-4 and 40-3 is that the combined isolation select valveEPI/SEL is provided in the same location as the combined isolation pilotvalve EPI/POV. Thus, the isolation select valve EPI/SEL in embodiment40-4 select the brake signal on port CVC or the signal from the electriccontrol valve ECV as the control signal for port passage 420 of thebrake cylinder valve BCV. The valve 466 is the same pneumatic valve aspart of the EPI/POV valve in FIGS. 3B and 4B. In its first position,valve 466 connects the brake signal port CVC directly through to thecontrol passage 420 of the brake cylinder valve BCV and blanks the portfor the output passage 422 of the electric control ECV.

[0097] An electrical valve 484 is spring biased to a first positionconnecting the control port or passage 486 of the valve 466 to exhaust.When activated, the valve 484 connects the control passage 486 for valve466 to the brake pipe passage 440. Thus, when 484 is activated, aminimum value of brake pipe pressure for example, 50 PSI throughpassages 440 and 486 will move valve 466 to its second positionconnecting the output passage 422 of the electrical control valve ECV tothe control port passage 420 of the brake cylinder valve BCV. The brakesignal passage 412 is blocked in this second position of the valve 466.Thus, the electrical valve 484 in combination with the brake pipepressure acts as the isolation portion of the combined isolation/selectvalve EPI/SEL. When deactivated, valve 466 isolates the output 422 fromthe electric control valve ECV from the brake cylinder valve BCV.

[0098] As illustrated in FIG. 5B, the valve 468 is substituted for thevalve 484 to produce combined isolation and pilot valve EPI/POV. Thecircuit in FIG. 5B for the fourth embodiment of the car control device40-4 is structural and operationally identical to that in FIG. 4B forthe third embodiment 40-3.

[0099]FIGS. 6A and 6B illustrate a fifth embodiment of the car controldevice 40-5. This fifth embodiment differs from the other embodiments inthat it does not use a brake cylinder valve BCV. The output passage 422of the electrical control valve ECV is connected to the isolation valveEPI which is shown including the valve 466. The isolation valve EPI is apilot valve which is spring biased to a first position (shown) where itsoutput 472 is connected to the exhaust and the output passage 422 of theelectric control valve ECV is blocked. The brake pipe port BPC isconnected as one of the control ports passage 440 of the valve 466. Thisis balanced against the spring and a passage 488 which is a pilotpressure from the emergency control port ERC. When the brake pipe isfully charged initially or after a release, the valve 466 is moved to asecond position which connects the output passage 422 of the electriccontrol valve ECV to the output 472 of the valve 466. When the brakepipe pressure is reduced to produce a conventional braking signal, theisolation valve EPI moves to the first position shown cutting off theelectric control valve ECV from the output 472. The output 472 of theisolated valve EPI is connected to the select valve SEL, which isconnected to exhaust, to be compared against the brake signal on brakesignal port CVC. The higher of the two is provided on passage 414 whichis connected to the brake cylinder port BCC.

[0100] The EPI valve 466 of FIG. 6A provides a pneumatic means ofallowing a conventional application or release to be made by theconventional control valve thru the “SEL” valve. This car control device40-5 does not provide the previous feature of ‘protecting’ against aninadvertent brake application by the electrical control valve ECV.

[0101] The car control valve 40-5 as illustrated in FIG. 6B may beoperable as a stand alone device in combination with the pipe bracket 30and the adaptor plate 42. The isolation valve is a combination isolationand pilot valve EPI/POV as in the previous embodiments including valves466 and 468. The emergency reservoir port ERC is connected throughpassages 406 and 436 to valve 468 as a supply input for the valve 466.The valve 466 is controlled by the brake pipe pressure in passage 440.Passage 448 is blanked. As in the previous embodiments, including aseparate select valve SEL, a blanking plate 458 is inserted whichconnects the output of the isolation pilot valve EPI/POV 472 directly tothe passage 414 of the brake cylinder port BCC.

[0102] Although the present invention has been described and illustratedin detail, it is to be clearly understood that the same is by way ofillustration and example only, and is not to be taken by way oflimitation. The spirit and scope of the present invention are to belimited only by the terms of the appended claims.

What is claimed:
 1. An electropneumatic retrofit unit for a pneumaticbrake control valve having a pipe bracket and an emergency brake portionand a service brake portion connected to said pipe bracket at first andsecond faces, said pipe bracket having passages connecting a brake pipeport, a brake cylinder port and an emergency reservoir port to saidfaces, the retrofit unit comprising: a plate for mounting at and sealingsaid first face; and a unit for mounting at said second face andincluding an electrical control valve, connected to said passage forsaid emergency reservoir port, a venting port and an output port whensaid unit is mounted, for selectively connecting said output port tosaid venting port for releasing a brake or to said emergency passage forapplying said brake, and a pneumatic emergency valve, responsive topressure in said passage for said brake pipe, for selectively connectingsaid passage of said brake cylinder port with said passage of saidemergency reservoir port in response to an emergency signal in saidbrake pipe port passage and connecting said brake cylinder port passagewith said output of said electrical control valve in absence of saidemergency signal in said brake pipe port passage, when said unit ismounted.
 2. A retrofit unit according to claim 1 , including aregulating valve connecting said emergency reservoir port passage tosaid pneumatic emergency valve.
 3. A retrofit unit according to claim 1, including a charging choke and check valve connecting said brake pipeport passage to said emergency reservoir port passage for charging anemergency reservoir from said brake pipe through said unit.
 4. Aretrofit unit according to claim 1 , including electronics on said unitfor operating said electrically controlled valve, and transducersconnected to said electronics for sensing pressure in said outlet ofsaid electrical control valve and in said brake cylinder port passage.5. A retrofit unit according to claim 4 , including transducersconnected to said electronics for sensing pressure in said brake pipeport passage.
 6. A retrofit unit according to claim 1 , wherein saidsecond face is the face to which said emergency portion would beconnected.